by Michele Chabin, Special for USA TODAY

by Michele Chabin, Special for USA TODAY

JERUSALEM â?? After Israel's military shot down a drone Thursday, suspicion quickly fell on Hezbollah, which denied sending the unmanned aircraft.

The militant Lebanese Hezbollah group denied responsibility for sending the drone in a one-line statement that flashed as an urgent news bar on the group's Al Manar TV.

Israeli Prime Minister Netanyahu, whose helicopter was temporarily grounded as a result of the situation, called the drone - the second one shot down by Israel in the past six months - "a very serious issue" and said he viewed the infiltration attempt with "utmost gravity."

"On my way here in the helicopter, I was told that there is an infiltration attempt of a drone inside the skies of Israel," Netanyahu said in the northern Arab-Israeli town of Daliyat al-Karmel. "We will continue to do everything necessary to safeguard the security of Israel's citizens."

The incident was likely to raise already heightened tensions between Israel and Hezbollah, a bitter enemy that battled Israel to a stalemate during a month-long war in 2006.

Tal Inbar, who heads Israel's Space Research Center at the Fischer Institute for Air & Space Strategic Studies, said that "even a drone with a small amount of high explosives could be directed to high-level" Israeli targets, including the country's national gas platform and power stations.

Lt. Col. Peter Lerner, a military spokesman, said the unmanned aircraft was detected as it was flying over Lebanon and tracked as it approached Israeli airspace.

Lerner said the military waited for the aircraft to enter Israeli airspace, confirmed it was "enemy," and then an F-16 warplane shot it down. The drone was shot down roughly five miles off the coast of the northern Israeli city of Haifa.

"Iran is distributing military technology both to the Assad regime in Syria and to Hezbollah in Lebanon. So if Hezbollah is experimenting with technology, it means Iran is experimenting as well," he said.

"We know from Lebanon's own media that Israel was already doing many over-flights over Lebanon, and it will continue," he said.

Despite the provocation, which he said might be Hezbollah's way of flexing its political muscles prior to Lebanese elections slated for June, Nisman doesn't expect an all-out response from Israel.

"This isn't a red line Israel is willing to act on, and neither is Hezbollah, which is being criticized for supporting Assad's regime," he said. "Neither side wants to be blamed for a military escalation."

Lebanon's state-run National News Agency reported that Israeli warplanes flew over the Christian town of Jezzine and the highlands of the Iqlim al-Tuffah province, a Hezbollah stronghold in southern Lebanon, Thursday morning.

The Lebanese army also reported Israeli jets violated Lebanese airspace on Tuesday and Wednesday. Israel has stepped up its flights over Lebanon amid fears that Hezbollah is taking advantage of the chaos caused by the Syrian civil war.